The rdpContext gets an event which will
get set if an error occoured in a channel.
If a thread or a void callback has to report an
error it will get signaled by this system.
The function with the same name is defined in multiple libraries
(libfreerdp-shadow.so, libfreerdp-server.so), which might confuse
the dynamic linker at runtime, binding a wrong version of the function
and thus causing segmentation faults.
Since remdesk_virtual_channel_write()s aren't used outside the files
they are defined in, we can declare them static to make them invisible
to the linker.
winpr is now always build as single library.
The build option MONOLITHIC_BUILD doesn't influence this behavior anymore.
The only exception is winpr-makecert-tool which is still build as extra
library.
This obsoletes complex_libraries for winpr.
